1. Field of the Invention
The present invention relates generally to heat exchangers for motor vehicles and, more specifically, to a beaded plate and method of making same for a heat exchanger in a motor vehicle.
2. Description of the Related Art
It is known to provide plates for a heat exchanger such as an oil cooler in a motor vehicle. Typically, opposed plates carry a first fluid medium in contact with an interior thereof while a second fluid medium contacts an exterior thereof. Typically, the first fluid medium is oil and the second fluid medium is air. Where a temperature difference exists between the first and second fluid mediums, heat will be transferred between the two via heat conductive walls of the plates.
It is also known to provide corrugated fins or ribs sandwiched between pairs of plates of a heat exchanger such as an oil cooler that act as a turbulator to increase the fluid side heat transfer coefficient while having to accept an appreciable amount of fluid side pressure drop. One known method of making such a construction is to physically insert a corrugated fin into the space between the plates after the plates have been manufactured. This is an extremely difficult process since the corrugated fin to be inserted between the plates is extremely thin and subject to deformation during the insertion process.
It is also known to provide beaded plates for a heat exchanger in which beads define a plurality of passageways between the plates for movement of a fluid therethrough to increase the surface area of conductive material available for heat transfer to cause turbulence of the fluid carried between the plates. An example of such a heat exchanger is disclosed in U.S. Pat. No. 4,600,053. In this patent, each of the plates has a plurality of beads formed thereon with one plate having one distinct variety of beads and the other plate having another distinct variety of beads. The beads of the plates contact each other and are bonded together to force fluid to flow therearound. The beads are aligned in rows in which one row has an "A" pattern and the adjacent or next row has a "B" pattern in which the beads are aligned with spaces of the A pattern. The rows are repeated in an AB pattern in which the beads in the A rows are aligned longitudinally or downstream with each other and the beads in the B rows are aligned longitudinally or downstream with each other.
Although the above heat exchangers have worked well, it is desirable to eliminate the use of a turbulator between the plates of a heat exchanger. It is also desirable to provide beaded plates for a heat exchanger having a repeating row pattern of non-aligned beads. It is still desirable to provide beaded plates for a heat exchanger that offer less resistance to flow than equal-sized turbulated heat exchangers with comparable heat rejection.